A sterilization process that applies high-energy rays has an advantage in that medical formed articles can be sterilized all together in a state in which the medical formed articles are packed in a cardboard box or a plastic case used for transportation, for example. Therefore, such a sterilization process is widely used as a simple and reliable sterilization method.
It is known that a hydrogenated block copolymer that exhibits excellent transparency, heat resistance, flexibility, and the like, and can be sterilized by steam, can suitably be used to produce a medical formed article (e.g., vial, infusion bag, syringe, or culture vessel) (see Patent Literature 1 to 4).
It is known to mix an antioxidant (e.g., phenol-based antioxidant, phosphorus-based antioxidant, or sulfur-based antioxidant) with a hydrogenated block copolymer in order to prevent coloration and a decrease in strength due to oxidative degradation during forming (molding) (see Patent Literature 2 to 4).
Patent Literature 4 discloses that a container produced by forming a hydrogenated block copolymer can be sterilized by applying electron beams or γ-rays.
However, Patent Literature 4 merely discloses that a phosphorus-based antioxidant, a phenol-based antioxidant, a sulfur-based antioxidant, and the like may be used to prevent oxidative degradation that may occur when forming a hydrogenated block copolymer to produce a container, and a phosphorus-based antioxidant is preferable due to a capability to reduce coloration. Patent Literature 4 does not disclose the type and the amount of an antioxidant that is advantageous when sterilizing a container by applying electron beams or γ-rays.